package com.ecust.Util;

import org.xukai.common.ArrayList;



import java.util.EmptyStackException;



public class Stack {



	private ArrayList elementData = new ArrayList();

	

	public void push(Object o){

		elementData.add(o);

	}

	

	public Object pop(){

		if (isEmpty()) {

			throw new EmptyStackException();

		}

		return elementData.remove(elementData.size()-1);

	}

	

	public Object peek(){

		if (isEmpty()) {

			throw new EmptyStackException();

		}

		return elementData.get(elementData.size()-1);

	}



	public boolean isEmpty(){

		return elementData.size() == 0;

	}



	public int size(){

		return elementData.size();

	}



	public void display() {

		elementData.display();

	}

}
